NMR in Analysis of the Nutritional Value of Lipids from Muscles and Livers of Wild Amazonian Fishes with Different Eating Habits over Seasonal Variation

Lipid composition of the Amazonian fishes remains unexplored although fishes in general show very high nutritional potential. Endogenous and environmental factors can influence the lipid contents of fishes among which, in the Amazon River, seasonal dynamics influences stand out. Herein, nine most consumed fish species were analyzed and their lipid composition evaluated in terms of effects of tissue from where were extracted, season of the Amazon River and the fish eating habits. Higher amounts of lipids were obtained from livers than dorsal muscles in all studied species. Statistical analysis has shown that Amazonian fishes present different lipid profiles according to their eating habits, which mainly comprises saturated fatty acids to distinguish detritivorous livers, and linolenic acid, cholesterol, polar lipids for carnivorous and piscivorous fish muscles. Furthermore, in Amazonian fish, some very important lipids for human nutrition are present, such as omega 3 and 6 fatty acids whose availability depended on the tissue metabolism and fishes’ eating habit along the seasonal periods. For example, our findings indicate that the piscivorous fish C. monoculus presented higher levels of linoleic acid for liver than linolenic acid and the opposite occurred for muscles. The omega 6 and 3 fatty acids ratio was influenced by the season dynamic of the Amazon River and availability of food according with each specific eating habit, poiting mainly to the piscivorous fishes as the healthiest fish for human consumption.